This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A372020 #9 Apr 16 2024 10:26:41
%S A372020 1,4,-4,4,156,-1212,5628,196,-251620,2500484,-12608772,16004,
%T A372020 671151260,-7039845180,37258827516,1585476,-2133978944740,
%U A372020 23052545651460,-125166709730820,174117124,7480512144282780,-82265332158299580,453899597102224380,20390254020
%N A372020 G.f. A(x) satisfies A(x) = ( 1 + 16*x*A(x)/(1 - x*A(x)) )^(1/4).
%F A372020 a(n) = (1/(n+1)) * Sum_{k=0..n} 16^k * binomial(n/4+1/4,k) * binomial(n-1,n-k).
%o A372020 (PARI) a(n) = sum(k=0, n, 16^k*binomial(n/4+1/4, k)*binomial(n-1, n-k))/(n+1);
%Y A372020 Cf. A372018, A372019.
%Y A372020 Cf. A372005.
%K A372020 sign
%O A372020 0,2
%A A372020 _Seiichi Manyama_, Apr 15 2024